The present invention relates to an image forming apparatus such as a printer.
As an image forming apparatus such a printer, an upright-type image forming apparatus is generally known. For example, Japanese Laid-open Patent Application No. 2003-302889 discloses such an upright-type image forming apparatus, in which a paper feed tray (recording sheet storage unit) for storing papers as recording sheets and a paper output tray (recording sheet receiving unit) are arranged back and forth with these trays positioned upright.
In this image forming apparatus, the paper feed tray is arranged higher than the paper output tray, so that a paper conveyance passage extending from a lower part of the paper feed tray to a lower part of the paper output tray for conveying a paper is bent to form a substantially U-shaped configuration. An image forming unit which forms an image on a paper is positioned intermediate of this paper conveyance passage at an extension extending downward from the lower part of the paper feed tray.
More specifically, the image forming unit includes a developer unit equipped with a toner cartridge and a developing roller, and a fixing device for thermally fixing developer that is transferred on a paper. The image forming unit is configured such that the fixing device is positioned below the developer unit on the paper conveyance passage.
However, in this image forming apparatus, because the fixing device is positioned below the developer unit, heat generated at the fixing device rises to the developer unit. This may cause the developer unit to be heated disadvantageously, and as a result heat deterioration of the developer may occur. Further, in this image forming apparatus, the paper conveyance passage extends downward from the lower part of the paper feed tray. In other words, the substantially U-shaped paper conveyance passage is configured such that a vertical distance from the lower part of the paper feed tray to the bottom portion of the conveyance passage is greater than a vertical distance from the bottom portion of the paper conveyance passage to the lower portion of the paper output tray. This causes the vertical distance of the image forming apparatus to be increased around the paper feed tray, so that the paper feed tray is positioned at a higher location. Therefore, it becomes difficult to load papers into the paper feed tray, which leads to deteriorated operationality of the image forming apparatus.
In view of the foregoing drawbacks of the prior art, the present invention seeks to provide an upright-type image forming apparatus which can restrict heat deterioration of the developer as well as an increase in the size of the apparatus in the vertical direction around a recording sheet storage unit, to thereby improve the operationality of the image forming apparatus.